10 years ago i wrote a php web chat in 2 hours or so. I pretty much never look at it but the tinestamps suggest it always worked.

I could add more features to it and those will also work.

A friend once worked on an application with a huge team. He often pointed out the window at a large costuction site with a comparable number of people working. He made countless jokes about real work, a real system, real organisation etc Then one day the building was finished and their application kept crashing in production.